Wisconsin Administrative Code
Department of Natural Resources
NR 800 - Environmental Protection - Water Supply
Chapter NR 811 - Requirements For The Operation And Design Of Community Water Systems
Subchapter II - Source Development - Groundwater
Section NR 811.13 - Well filling and sealing

Universal Citation: WI Admin Code ยง NR 811.13

Current through August 26, 2024

Filling and sealing of community water system wells are subject to all of the following requirements:

(1) CRITERIA FOR FILLING AND SEALING. The owner shall permanently fill and seal all unused permanent wells, test wells, and monitoring wells for permanent wells or test wells unless the department agrees to the delayed filling and sealing of the well as part of an extended well filling and sealing agreement. Wells shall be filled and sealed in accordance with all of the following criteria:

(a) Test wells and monitoring wells constructed as part of the test well or permanent well construction and test pumping evaluation processes shall be permanently filled and sealed prior to placing the permanent well in service unless the department approves the wells to remain in service in accordance with the requirements under s. NR 811.12 (21).

(b) Permanent wells with one or more water quality parameters exceeding a primary drinking water standard under ch. NR 809 shall be permanently filled and sealed unless the owner obtains department approval to continue the well in service and only if department approved water treatment is installed to provide point-of-entry water quality compliance or the owner obtains an extended well filling and sealing agreement from the department under s. NR 810.22. The owner shall contact the department and obtain written department approval for the filling and sealing of contaminated wells. The department may require more stringent filling and sealing requirements to protect lower aquifers from additional contamination.

(c) The department may allow existing permanent wells that are not constructed in accordance with the minimum requirements of this chapter to remain in service if the well water quality continues to meet all of the primary drinking water standards under ch. NR 809 or if department-approved water treatment is installed to provide point-of-entry water quality compliance. All ungrouted municipal wells shall be immediately reconstructed by grouting in a liner casing to a depth approved by the department or the well shall be taken out of service and filled and sealed.

(2) QUALIFICATIONS OF PERSONS FILLING AND SEALING WELLS. All wells shall be filled and sealed by a person who meets all of the following qualifications:

(a) For wells located within a municipal water system, the person shall be a licensed well driller, a licensed pump installer, a water system operator certified under s. 281.17 (3), Stats., working for the municipal water system, or a person under the supervision of a licensed well driller, licensed pump installer, or a water system operator certified under s. 281.17 (3), Stats., working for the municipal water system.

(b) For wells not located within a municipal water system, the person shall be a licensed well driller, a licensed pump installer or a person under the supervision of a licensed well driller or licensed pump installer.

(3) TEMPORARY ABANDONMENT. When a well is temporarily removed from service, the top of the well casing shall be sealed with a watertight threaded or welded cap. The well shall be permanently filled and sealed no later than 5 years after the well is temporarily abandoned. The department may enter into a written extended well filling and sealing agreement with the owner under s. NR 810.22 to allow an unused or standby well to remain operational for more than 5 years after the well is temporarily abandoned.

(4) PRE-FILLING AND SEALING REQUIREMENTS.

(a) All debris, pumps, piping, ungrouted liner pipe that can be removed, inner ungrouted casings and well screens, and any other obstruction known to be in the well shall be removed if possible before the well is filled and sealed.

(b) Well casing pipe may be removed from a well to be abandoned if the end of the pipe remains in the well sealing material as the pipe is pulled from the well.

(c) Wells that have uncertain construction details shall be televised prior to filling and sealing if required by the department to allow for a proper filling and sealing.

(d) All casings and liner pipes located within ungrouted annular spaces and that cannot be removed from a well prior to filling or sealing shall either be shot or ripped in place prior to filling and sealing of the well. All of the following minimum requirements shall be met:
1. The casing shall either be perforated using projectiles fired perpendicular and completely through the casing or liner pipe or shall be vertically ripped.

2. There shall be 4 shots or one rip per each 5 feet of casing.

3. Each shot shall be a minimum of 0.4 inches in diameter. Each rip shall have a minimum width of 0.25 inches and a minimum length of 12 inches.

4. Each successive shot or rip shall be rotated by 90 degrees.

5. The portion of the well with a casing or liner pipe to be shot or ripped shall be completely filled inside and outside by pressure grouting with neat cement from the inside out and from the bottom up in accordance with s. NR 811.12 (14).

(5) FILLING AND SEALING MATERIALS AND LIMITATIONS. All wells shall be filled and sealed using any of the following materials:

(a) Neat cement grout, sand-cement grout, or concrete meeting the specifications in s. NR 811.12 (14) (a). Powdered bentonite shall not be added to neat cement grout.

(b) Department approved slow-hydrating bentonite chips with the following limitations:
1. The well diameter shall be 4 inches or larger.

2. The depth of chip placement shall not exceed 500 feet.

3. The depth of standing water in the well shall not exceed 350 feet.

4. Fine particles and dust contained in the bags of bentonite chips shall be prevented from entering the well by allowing the chips to tumble under their own weight down a coarse mesh screen into the well. The chips shall be poured across the screen and into the well at a rate not to exceed emptying the bag in 3 minutes.

5. The depth of chips shall be monitored a minimum of once every calculated 50 feet to monitor for bridging of chips. Any chip bridges shall be removed.

6. Water from a clean, known bacteriologically safe source shall be poured down the well on a continuous basis as the chips are being introduced into the well in order to hydrate all of the chips. Water shall be continuously introduced until the water level rises to the top of the well casing and stays there.

(c) Pea gravel that is round, washed to be free of sand and other fine materials, disinfected and having a maximum diameter of 0.375 inches, may be poured into a well without the use of a conductor pipe if the well is sounded at 50-foot intervals to ensure that bridging of the gravel does not occur.

(6) GENERAL FILLING AND SEALING REQUIREMENTS. Filling and sealing methods shall meet all of the following requirements:

(a) All wells shall be filled from the bottom of the well up to the ground surface using approved materials unless it is necessary to terminate the filling and sealing below the ground surface to accommodate construction over the well. Well casings and filling and sealing materials may be terminated as much as 3 feet below the ground surface or to a depth below any future building foundation to accommodate construction over the well.

(b) The bottom end of the conductor pipe shall be submerged in the sealing material at all times.

(c) Sealing materials shall be placed by use of a conductor pipe or by means of a dump bailer except when approved bentonite chips or pea gravel are used. Bentonite chips may be poured into the well in accordance with sub. (5) (b). Pea gravel may be poured into the well in accordance with sub. (5) (c). Conductor piping used for pressure methods shall meet the requirements of s. NR 811.12 (14) (b) 8. for well grouting. Conductor piping for non-pressure methods shall be one of the following:
1. Metal pipe.

2. Rubber-covered hose reinforced with braided fiber or steel and rated at least 300 psi.

3. For use at depths less than 100 feet, thermoplastic pipe rated for at least 100 psi, including any of the following:
a. Polyvinyl chloride (PVC).

b. Chlorinated polyvinyl chloride (CPVC).

c. Polyethylene (PE).

d. Polybutylene (PB).

e. Acrylonitrile butadiene styrene (ABS).

(7) SPECIAL FILLING AND SEALING REQUIREMENTS. To fill and seal a well, the owner shall have a person who meets the qualifications under sub. (2) fill and seal the well to prevent it from acting as a channel for the vertical movement of contamination or groundwater, by the following applicable method:

(a) Monitoring wells. Monitoring wells constructed to ch. NR 141 requirements shall be filled and sealed in accordance with ch. NR 141 requirements.

(b) Flowing wells. For flowing wells, the flow shall be confined and the well shall be filled in accordance with par. (c), (d), or (e) or sealed in accordance with sub. (6) using neat cement grout applied by a pressure method.

(c) Drift or other unconsolidated wells. For drift or other unconsolidated wells, the well shall be completely filled from the bottom up with concrete, sand cement grout, neat cement, or approved slow-hydrating bentonite chips. Sealing materials shall meet the requirements of sub. (5). An attempt shall be made to remove any inner ungrouted well casings and screens from gravel-pack wells prior to filling. If the well casings and screens cannot be removed, an attempt shall be made to remove as much gravel pack as possible using air or water or both jetting techniques and the interior and exterior of the ungrouted casings and screens shall then be sealed from the bottom up in accordance with sub. (6) using neat cement applied by a pressure method.

(d) Bedrock formation wells. Wells completed in bedrock formations shall be completely filled from the bottom up with concrete, sand-cement, neat cement, or approved slow-hydrating bentonite chips. Sealing materials shall meet the requirements under sub. (5). Wells shall be filled and sealed in accordance with the following formation specific requirements, as applicable:
1. 'Maquoketa Shale.' As an alternative for uncontaminated bedrock wells deeper than 250 feet or for wells cased and grouted through the Maquoketa Shale formation, chlorinated, sand-free pea gravel may be used to fill the open drillhole from the bottom of the well up to the 250-foot depth or to a depth 20 feet below the bottom of the protective casing, whichever is deeper. The owner shall contact the department for specific filling and sealing requirements where the top or the bottom of the Maquoketa Shale formation is exposed in the open drillhole.

2. 'Cambrian Sandstone and Eau Claire formations.' Minimum 40-foot thick plugs of sealing materials meeting the requirements of under sub. (5) shall be centered at the top of the uppermost Cambrian Sandstone formation and at the top of the Eau Claire formation where these formations are open in the drillhole.

(e) Dug and bored wells. The cover and the top curbing or concrete wall shall be removed to a depth of 5 feet below grade for dug or bored wells. Concrete or rock curbing materials may be caved into the drillhole as the well is being sealed only if performed in a manner to prevent bridging.
1. If constructed in unconsolidated formations, the well shall be filled from the bottom up using clean clay or silt, clean native soil, concrete, sand-cement, neat cement, or approved slow-hydrating bentonite chips or a combination of the above. Sealing materials shall meet the requirements of sub. (5).

2. If constructed partially or completely into bedrock, the well shall be filled from the bottom up to the ground surface with concrete, sand-cement, neat cement, approved slow-hydrating bentonite chips or a combination of the above except that if bedrock is encountered below the ground surface, these materials shall be placed to a point at least 2 feet above the top of the bedrock. The remainder of the well may be filled and sealed with any of the materials listed under subd. 1. Sealing materials shall meet the requirements under sub. (5).

3. Dug or bored wells 18 inches in diameter and smaller shall be filled by means of a conductor pipe, or tremie pipe, except when slow-hydrating bentonite chips are used as specified in sub. (5) (b) or when clean clay or silt or clean native soil is used and the dug or bored well is 25 feet deep or less.

(8) FILLING AND SEALING REPORTS. The person who filled and sealed the well shall file a filling and sealing report with the department, on forms provided by the department, within 30 days after the completion of the well filling and sealing. The report shall be completely filled out in accordance with the information known and shall include complete information on the depths and types of sealing materials used. Well drillers and pump installers shall report to the department any unused or wells that have not been filled and sealed on the property of which they have knowledge.

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